About This Calculator

The NovoEight Dose Calculator is an informational resource designed to assist healthcare professionals in estimating dosing for NovoEight® (turoctocog alfa) for patients with hemophilia A. The calculations are based on established pharmacokinetic formulas for Factor VIII replacement therapy. This tool should be used for educational and reference purposes only and must not replace professional clinical judgment, patient assessment, or the official Prescribing Information.

Outputs Explained

After entering the required patient data, the calculator provides the following key outputs:

• Calculated Dose: The theoretical dose in International Units (IU) required to achieve the desired therapeutic target, rounded to the nearest whole number.
• Recommended Vials: A suggested combination of available NovoEight® vial strengths (250, 500, 1000, 1500, 2000, and 3000 IU) to most closely match the calculated dose. The algorithm prioritizes using the fewest number of vials.
• Actual Administered Dose: The total IU dose based on the sum of the recommended vial strengths. This value may be slightly higher than the calculated dose due to rounding up to the nearest available vial combination.
• Total Reconstitution Volume: The total volume in milliliters (mL) required for administration, based on a standard reconstitution volume of 4 mL per vial for all strengths.

How to Use the Tool

1. Enter Patient Weight: Input the patient’s body weight and select the appropriate unit (kg or lbs). The tool will automatically convert lbs to kg for calculation.
2. Select Calculation Mode:
   • Choose On-Demand Treatment for calculating a dose to manage an active bleed.
   • Choose Prophylaxis for calculating a routine preventative dose.
3. Specify Dosing Target:
   • For On-Demand, select the bleed severity (Minor, Moderate, or Major), which sets a standard desired Factor VIII increase, or select ‘Custom’ to manually input a target percentage.
   • For Prophylaxis, enter the prescribed dose in IU per kilogram (IU/kg).
4. Calculate: Press the “Calculate Dose” button to view the results. Use the “Reset” button to clear all fields.

Dosing Overview

The dosing strategy for NovoEight® depends on the clinical scenario, whether it’s for on-demand treatment of bleeding episodes or for routine prophylaxis.

On-Demand Treatment

The dose is determined by the patient’s weight and the desired increase in Factor VIII activity. The calculator uses the following standard formula:

Dose (IU) = Body Weight (kg) × Desired Factor VIII Increase (%) × 0.5 (IU/kg per % increase)

The tool presets the desired Factor VIII increase based on bleed severity, which can be customized as needed by the clinician.

Prophylaxis

For routine prophylaxis, the dose is based on a prescribed regimen, typically ranging from 20 to 50 IU/kg administered several times per week. The calculator determines the total dose using this formula:

Dose (IU) = Body Weight (kg) × Prescribed Dose (IU/kg)

Switching Patients to NovoEight®

When transitioning a patient from another Factor VIII product, the dosing and administration schedule should be guided by their previous regimen and current clinical status. Close monitoring of Factor VIII activity levels and clinical response is recommended during the transition period. All changes in treatment should be managed by a healthcare professional experienced in hemophilia care.

Missed Dose Information

If a patient misses a scheduled prophylactic dose of NovoEight®, they should administer the dose as soon as they remember. They should then continue with their regular dosing schedule. Patients should not take a double dose to make up for a missed one. If there are any questions or concerns about a missed dose, the patient or caregiver should contact their healthcare provider.

Safety Alerts

Frequently Asked Questions (FAQ)

How is the on-demand dose calculated?

It uses the standard formula: Dose (IU) = Body Weight (kg) × Desired Factor VIII Increase (%) × 0.5. For example, a 70 kg patient needing a 30% increase would require 70 × 30 × 0.5 = 1,050 IU.

What is the formula used for prophylaxis calculations?

The prophylaxis calculation is: Dose (IU) = Body Weight (kg) × Prescribed Dose (IU/kg). For a 70 kg patient on a 30 IU/kg regimen, the dose would be 70 × 30 = 2,100 IU.

Can I use pounds (lbs) for the patient’s weight?

Yes. Select the “lbs” unit toggle next to the weight input field. The calculator will convert the value to kilograms (1 lb ≈ 0.4536 kg) for the calculation automatically.

What are the preset Factor VIII targets for bleed severities?

The tool defaults to a 30% increase for ‘Minor’ bleeds, 50% for ‘Moderate’, and 90% for ‘Major’ bleeds. These can be overridden by selecting ‘Custom’.

How does the tool determine the vial combination?

The algorithm identifies the most efficient combination of available vial strengths (3000, 2000, 1500, 1000, 500, 250 IU) to meet or exceed the calculated dose, aiming to use the minimum number of vials to simplify preparation.

Why is the “Actual Administered Dose” different from the “Calculated Dose”?

The calculated dose is a precise theoretical value. Since medication is supplied in fixed-strength vials, the actual administered dose is the sum of the chosen vials, which is rounded up to the nearest practical combination. This ensures the patient receives at least the calculated therapeutic dose.

What is the reconstitution volume per vial?

The calculator assumes a standard reconstitution of 4 mL of sterile water for injection (SWFI) per vial, regardless of the IU strength, as per the product’s instructions for use.

What is the maximum weight the calculator accepts?

The calculator is designed for weights up to 250 kg (approximately 551 lbs) to prevent extreme calculations that fall outside typical clinical scenarios.

References

1. NovoEight® (turoctocog alfa) US Prescribing Information. Novo Nordisk A/S. U.S. Food and Drug Administration.
2. NovoEight® Official Healthcare Professional Website. Novo Nordisk.
3. NovoEight® European Public Assessment Report (EPAR). European Medicines Agency.
4. Guidelines for the Management of Hemophilia. World Federation of Hemophilia.